Technical Abstract:
Soil microbial community structure was investigated in a tomato field production system that utilized poultry manure compost, poultry manure, and hairy vetch cover crop as nitrogen sources. A randomized complete block design with four replicates was used. Treatments consisted of synthetic N, hairy vetch mulch, a mixture of hairy vetch and poultry manure compost (10 t/ha), three levels of poultry manure compost (5, 10, 20 t/ha), and two levels of poultry manure (2.5 and 5 t/ha). Plastic mulch was used in treatments without hairy vetch. Soil samples were taken at five different times during the growing season. Fatty acid analysis was used to characterize the total soil microbial community structure while two substrate utilization assays were used to investigate the community structure of copiotrophic bacteria and fungi. In all cases the seasonal effect was much greater than the treatment effect. Treatments with hairy vetch, vetch plus compost, and the highest level of compost were distinct from all other treatments on the basis of fatty acid composition. There was no significant treatment effect observed with the substrate utilization assay for copiotrophic bacteria. A very weak treatment effect was observed with the substrate utilization assay for fungi, with one of the compost treatments (10 t/ha) being different from all other treatments.